WiX: Old versions don't disappear in Add/Remove Programs list

Create a major upgrade. For example, use the MajorUpgrade element in WiX v3.5. http://www.joyofsetup.com/2010/01/16/major-upgrades-now-easier-than-ever/

An addendum to this - if the RemoveFeatures attribute of MajorUpgrade is included, and names specific features to remove from the previous install (but not all of the features), that will cause the previous entry to remain in Add/Remove programs. If RemoveFeatures is not included, all the features of the previous install will be removed, including the entry in Add/Remove programs.